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Description

A flaw was found in Open Cluster Management (OCM), the technology underlying Red Hat Advanced Cluster Management (ACM). Improper validation of Kubernetes client certificate renewal allows a managed cluster administrator to forge a client certificate that can be approved by the OCM controller. This enables cross-cluster privilege escalation and may allow an attacker to gain control over other managed clusters, including the hub cluster.

PUBLISHED Reserved 2026-03-24 | Published 2026-04-07 | Updated 2026-04-09 | Assigner redhat




HIGH: 8.2CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Problem types

Improper Certificate Validation

Product status

Default status
affected

Default status
affected

Timeline

2026-03-24:Reported to Red Hat.
2026-04-07:Made public.

Credits

Red Hat would like to thank Arnaud FEVRIER (Orange) for reporting this issue.

References

access.redhat.com/security/cve/CVE-2026-4740 vdb-entry

blog.arfevrier.fr/...luster-management-cross-cluster-escape/

bugzilla.redhat.com/show_bug.cgi?id=2450590 (RHBZ#2450590) issue-tracking

cve.org (CVE-2026-4740)

nvd.nist.gov (CVE-2026-4740)

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